1. Field of the Invention
The invention generally relates to an electrical extension cord, and in particular it relates to an electrical extension cord that slides smoothly over edges between various surfaces.
2. Description of the Related Art
Extension cords are often used to transmit power to locations that are removed from conventional electrical outlets. They provide a continuous connection between power sources and devices that require electricity to function properly, such as lights, tools and industrial equipment. Generally, an extension cord consists of an adapter, into which a plug that is attached to the device can be inserted, and an encased wire that travels from the adapter to the power supply. Each adapter can have either of two basic configurations: metallic prongs that project from a circular face in a perpendicular direction (a so-called “male adapter”) or openings that are embedded in the face (a so-called “female adapter”). The number of prongs present in male adapters can range from two to four, while the number and shape of the openings in female adapters are designed to receive prongs from a corresponding male adapter.
However, a significant problem is associated with the use of nearly all commercially available extension cords. Namely, each extension cord snags on edges between various surfaces because of the geometry of the interface between its adapter and its wire. This scenario usually develops when a user pulls or reels in the extension cord. In order to effectively utilize the extension cord, the user must access the cord, lift the adapter and reposition the adapter-wire interface on a flat surface. Doing so is usually a frustrating and time-consuming task. It can also be dangerous if, for example, the user is operating a portable power tool while freeing the cord. Hence, there is a pressing need for an extension cord that is specifically designed to slide smoothly over commonly encountered edges.
U.S. Pat. No. 4,679,877 to Ahroni (“Ahroni”) teaches an electric plug with snap-fitted housing components. However, an extension cord that has the plug of Ahroni would readily snag on edges.
U.S. Pat. No. 5,069,634 to Chiarolanzio (“Chiarolanzio”) discloses an electrical connection device that engages the plug and receptacle ends of electrical devices with extension cords or an electrical cord with a power receptacle. However, an extension cord that has the device of Chiarolanzio would readily snag on edges.
U.S. Pat. No. 6,517,373 B2 to Finke et al. (“Finke”) teaches a circular electrical connector. However, an extension cord that has the connector of Finke would readily snag on edges.
While these devices may be suitable for the particular purposes employed, or for general use, they would not be as suitable for the purposes of the present invention as disclosed hereafter.